In recent years, an increase in information processing capacity and a speedup in information processing speed of a personal computer have been demanded by reason of the spread of the Internet; accordingly, a larger capacity and a speedup in information transmission rate have been required also for a hard disk drive (HDD) incorporated into a personal computer.
Thermal assist recording is known as one of the techniques for intending a larger capacity (a higher recording density) of HDD (Patent Literatures 1 to 7 and Non Patent Literature 1). Thermal assist recording is to record while temporarily decreasing coercive force of magnetic particles by heating a recording medium immediately before recording. Thus, information is easily recorded in a recording medium even in the case of using magnetic particles with a large coercive force. Also, DSA (Dual Stage Actuator) system is known as another technique for intending a higher recording density (Patent Literatures 8 to 10). DSA system is to improve positioning accuracy of a recording and reproducing element (such as a magnetic head slider) by mounting an actuator element (such as a piezoelectric effect element) on a suspension substrate. Thus, a track pitch of a recording medium may be decreased and a higher recording density of HDD may be intended.
Incidentally, a suspension substrate, such that a lower conductor is provided through an insulating layer under a signal transmission wiring layer (a recording line and a reproducing line) for the purpose of achieving a lower impedance of a signal transmission wiring layer for reading and writing out of a recording and reproducing element, is disclosed in Patent Literature 11. Also, a suspension substrate having a structure in which a pair of signal transmission wiring layers is laminated through an insulating layer is disclosed in Patent Literature 12.